1. Field of the Invention
This invention relates to the field of electric stringed instruments and, more particularly to an instrument comprising interchangeable, electronics-containing modules which are fitted into an instrument body.
2. Discussion of the Related Art
Stringed instrument electronics are comprised of magnetic pickups arranged beneath the strings of guitars and like instruments, and having other electronic components which facilitate obtaining desired qualities of tonality, loudness, reverberation and timbre, qualities referred to in this discussion as `sound` and `tonal qualities`. Potentiometers regulate tonal qualities and volume. Switches regulate the electronic signal between pickups or different tonal qualities within the same pickup. Vibrations in the strings of a guitar induce electric signals in the coils of the pickup which are modified by switches and potentiometers and transmitted through the output wires from the guitar to an amplifier. Modification of musical sound utilizing different pickup designs and complementary electronic components can be achieved by the regrouping of pickups and electronic components.
Originally, electric guitar players had few choices in pickups giving different tonal qualities. Changes in styles of music and advances in pickup design, however, have spawned a large electronic market with many manufacturers, each producing numerous pickups. But, there has heretofore been no way for guitar players to conveniently have available to them a choice between various sounds in a single instrument, and guitarists have typically acquired numerous guitars, each with a particular electronic installation which produces distinct tonal qualities.
The exchange of guitar electronics in the known guitars generally requires technical assistance that is costly and time-consuming. Guitar players having technical expertise may exchange pickups and electronics themselves by removing the strings, unscrewing the casement for each pickup, installing the new pickups and restringing. Then, from the back of the guitar, they may remove a panel covering a relatively small cavity formed in the guitar body, and access electronic components which are installed through the back. Thus, each electronic component may be replaced individually and wired to the pickups.
The following U.S. patents suggest two approaches toward the replacement of pickups in guitars: U.S. Pat. No. 4,425,831 to Lipman, U.S. Pat. No. 5,029,511 to Rosendahl, U.S. Pat. No. 4,872,386 to Betticare, U.S. Pat. No. 5,252,777 to Allen, and U.S. Pat. No. 4,854,210 to Palazzolo. First, to obtain a modified musical sound without simply purchasing a new instrument or replacing the electronics as described above, the replacement of pickups can be achieved through a small opening in the back of the guitar which extends all the way through the body, permitting replacement of only one pickup at a time. Secondly, utilizing several shallow chambers in the front of the guitar permits the replacement of one or several pickups. But using either of these approaches, other electronic components are not replaced, and a full choice of desired tonal qualities is not provided.
An exchangeable guitar module which houses the electronic components and facilitates regrouping of electronic components is disclosed in French Patent No. 2-599-881. The disclosed device permits lateral insertion of an electronics module into a cut-out in the guitar body of equivalent depth as the module, but not cut entirely through the guitar body. Once installed via a groove in the guitar body and bolted, the device becomes integral to the structure of the guitar. The electronics-containing device is contiguous with the outside of the guitar body.
The disclosed French device has a number of significant disadvantages. Many of today's popular guitar body styles can be outfitted with lateral exchange devices only by having a separate module style for each body type. The lateral exchange device is bolted to the guitar body, requiring fastening tools external to the module, making this device not rapidly interchangeable. Also, securing the device to the guitar body via a groove cut into the guitar affords little space for natural expansion of materials due to changes in humidity and temperature.
One factor that has limited the development of rear entry interchangeable electronic modules is that typical guitar body construction is not conducive to having a large cavity or hole formed through the instrument without reducing the structural integrity of the guitar, so that the guitar body can fully withstand the tension placed on it by taut guitar strings. A cavity routed all the way through the guitar and made large enough to accommodate several pickups and all of the other electronic components would have a perimeter relatively close to the bridge and to the bottom of the fretboard on the neck. If such a cavity or hole was made in a conventional guitar design, a weak area would be created on either side where the neck connects to the guitar. For example, in conventional construction, three boards are glued together laterally to form the body of the guitar, and while the centerboard may also extend from the body to become the neck, many guitars have a bolt-on or glued in neck. In all three of these designs, if a large cavity is routed into the guitar body beneath the strings and extended laterally to accommodate a module containing not only the pickups but also the switches, wiring and potentiometers, the remaining wood mass would not be sufficient to support the tension of the strings, and the instrument would bow inward, thus raising the strings away from their normal position above fretboard, making the instrument unplayable.
For the foregoing reasons, there has been a need for a rear entry interchangeable electronics module for increased rapidity of electronic exchange, a module that would be placed into a cavity formed in the instrument body, such that the pickups would be automatically positioned beneath the strings without requiring time consuming removal of the strings or the individual exchange of pickups and electronic components, while maintaining the structural integrity of the instrument body and offering versatility by insertion into many body styles. Further, there has been a need for a rear insertion module having a sufficient thickness to accommodate installation of all of the electronic components on the current market, including the deeply set five way switch. To overcome the potential adverse effect on the structure of the instrument body of conventional wood construction by creating a large cavity between the bridge and fretboard, the use of a wide centerboard, neck-through-body construction would be desirable. Such a construction is occasionally utilized in custom-made guitars by laterally laminating different wood pieces on either sides of the pickup casements for the purpose of enhancement of the aesthetic qualities of the instrument. The use of a wide centerboard not simply for aesthetic reasons but for increased structural support, along with other significant modifications in typical guitar construction, comprise a design strategy for a rear insertion modular instrument, which will become clear in the description of the current invention.